Make all datetime objects fully timezone aware

This is most of the transition to Django 1.4 `USE_TZ = True`. We need to
ensure we don't mix aware and non-aware datetime objects when dealing
with datetimes in the code. Add a utc_now() helper method that we can
use most places, and ensure there is always a timezone attached when
necessary.

Signed-off-by: Dan McGee <dan@archlinux.org>

4 files changed, 19 insertions, 7 deletions

diff --git a/main/migrations/0050_auto__chg_field_package_compressed_size__chg_field_package_installed_s.py b/main/migrations/0050_auto__chg_field_package_compressed_size__chg_field_package_installed_s.py
index 7aa09596..8368ae2e 100644
--- a/main/migrations/0050_auto__chg_field_package_compressed_size__chg_field_package_installed_s.py
+++ b/main/migrations/0050_auto__chg_field_package_compressed_size__chg_field_package_installed_s.py
@@ -1,5 +1,6 @@
 # encoding: utf-8
 import datetime
+from pytz import utc
 from south.db import db
 from south.v2 import SchemaMigration
 from django.db import models
@@ -9,7 +10,9 @@ class Migration(SchemaMigration):
     def forwards(self, orm):
         db.alter_column('packages', 'compressed_size', self.gf('main.models.PositiveBigIntegerField')(default=0))
         db.alter_column('packages', 'installed_size', self.gf('main.models.PositiveBigIntegerField')(default=0))
-        db.alter_column('packages', 'last_update', self.gf('django.db.models.fields.DateTimeField')(default=datetime.datetime(2000, 1, 1)))
+        old_date = datetime.datetime(2000, 1, 1)
+        old_date = old_date.replace(tzinfo=utc)
+        db.alter_column('packages', 'last_update', self.gf('django.db.models.fields.DateTimeField')(default=old_date))
 
     def backwards(self, orm):
         db.alter_column('packages', 'compressed_size', self.gf('django.db.models.fields.BigIntegerField')(null=True))
diff --git a/main/migrations/0054_auto__add_field_donor_created.py b/main/migrations/0054_auto__add_field_donor_created.py
index f4d5b157..c96c0f5d 100644
--- a/main/migrations/0054_auto__add_field_donor_created.py
+++ b/main/migrations/0054_auto__add_field_donor_created.py
@@ -1,5 +1,6 @@
 # encoding: utf-8
 import datetime
+from pytz import utc
 from south.db import db
 from south.v2 import SchemaMigration
 from django.db import models
@@ -8,7 +9,9 @@ class Migration(SchemaMigration):
 
     def forwards(self, orm):
         # Adding field 'Donor.created'
-        db.add_column('donors', 'created', self.gf('django.db.models.fields.DateTimeField')(default=datetime.date(2000, 1, 1)), keep_default=False)
+        old_date = datetime.datetime(2000, 1, 1)
+        old_date = old_date.replace(tzinfo=utc)
+        db.add_column('donors', 'created', self.gf('django.db.models.fields.DateTimeField')(default=old_date), keep_default=False)
 
 
     def backwards(self, orm):
diff --git a/main/models.py b/main/models.py
index 4f2d64ea..7d017242 100644
--- a/main/models.py
+++ b/main/models.py
@@ -9,7 +9,7 @@ from django.contrib.auth.models import User
 from django.contrib.sites.models import Site
 
 from .fields import PositiveBigIntegerField, PGPKeyField
-from .utils import cache_function, make_choice, set_created_field
+from .utils import cache_function, make_choice, set_created_field, utc_now
 
 
 class UserProfile(models.Model):
@@ -515,7 +515,7 @@ class TodolistPkg(models.Model):
 def set_todolist_fields(sender, **kwargs):
     todolist = kwargs['instance']
     if not todolist.date_added:
-        todolist.date_added = datetime.utcnow()
+        todolist.date_added = utc_now()
 
 # connect signals needed to keep cache in line with reality
 from main.utils import refresh_latest
diff --git a/main/utils.py b/main/utils.py
index 8143ea6a..e7e47c53 100644
--- a/main/utils.py
+++ b/main/utils.py
@@ -5,6 +5,7 @@ except ImportError:
 
 from datetime import datetime
 import hashlib
+from pytz import utc
 
 from django.core.cache import cache
 
@@ -91,12 +92,17 @@ def retrieve_latest(sender):
     return None
 
 
+def utc_now():
+    '''Returns a timezone-aware UTC date representing now.'''
+    return datetime.utcnow().replace(tzinfo=utc)
+
+
 def set_created_field(sender, **kwargs):
-    '''This will set the 'created' field on any object to datetime.utcnow() if
-    it is unset. For use as a pre_save signal handler.'''
+    '''This will set the 'created' field on any object to the current UTC time
+    if it is unset. For use as a pre_save signal handler.'''
     obj = kwargs['instance']
     if hasattr(obj, 'created') and not obj.created:
-        obj.created = datetime.utcnow()
+        obj.created = utc_now()
 
 
 def groupby_preserve_order(iterable, keyfunc):